import jQuery from 'jquery';
// JavaScript Document
(function($) {
  $.fn.myScroll = function(options) {
    //默认配置
    var defaults = {
      speed: 40,  //滚动速度,值越大速度越慢
      rowHeight: 24, //每行的高度
    };
    var opts = $.extend({}, defaults, options), intId = [];

    function marquee(obj, step) {

      obj.find('ul').animate({
        marginTop: '-=1',
      }, 0, function() {
        var s = Math.abs(parseInt($(this).css('margin-top')));
        if (s >= step) {
          $(this).find('li').slice(0, 1).appendTo($(this));
          $(this).css('margin-top', 0);
        }
      });
    }

    this.each(function(i) {
      var sh = opts['rowHeight'], speed = opts['speed'], _this = $(this);
      intId[i] = setInterval(function() {
        if (_this.find('ul').height() <= _this.height()) {
          clearInterval(intId[i]);
        } else {
          marquee(_this, sh);
        }
      }, speed);
      _this.hover(function() {
        clearInterval(intId[i]);
      }, function() {
        intId[i] = setInterval(function() {
          if (_this.find('ul').height() <= _this.height()) {
            clearInterval(intId[i]);
          } else {
            marquee(_this, sh);
          }
        }, speed);
      });
    });
  };
})(jQuery);
